Lubricating means for pneumatic door checks, closers, and the like



July 28, 1953 B. A. QUINN LUBRICATING MEANS FOR PNEUMATIC DOOR CHECKS, CLOSERS, AND THE LIKE Filed Dec. 29, 1951 zl; INVENTOR.

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Patented July 28, 1953 OFFICE LUBRICATING MEANS FOR PNEUMATIC DOOR CHECKS, CLOSERS, AND THE LIKE Bert A. Quinn, St. Paul, Minn.

Application December 29, 1951, Serial No. 264,050

6 Claims. (01. lo -66) present invention relates to the provision I of an improved means for lubricating of door closers and analogous devices of the spring- .operated pneumatically-controlled type, which are commonly referred to in the art as, and may be hereinafter referred to as, pnuematic door checks. More specifically stated, my invention relates to the lubrication of pneumatically-controlled spring-operated door closers, otherwise referred to as door checks, of the kind comprising an elongated cylinder, a plunger-rod working through one end of the cylinder, a piston mounted on the inner end of the plunger-rod, and a door-closing compression spring mounted in the cylinder over the plunger-rod and compressed between the piston-equipped end of the plungerrod and one end portion of the cylinder. Door closers or checks of this type have from their inception presented a difilcult lubrication problem and the absence of a commercially satisfactory solution to this problem has resulted in rapid wearing out of certain of the vital parts, such as the pistons or piston seals of commercial devices of this character, at least in the absence of proper and frequent manual lubrication, which is seldom provided by the users of such devices. The pistons or plungers of door checks and analogous devices of the character described are usually equipped with expandable sealing devices, which contact the interior of the cylinder to prevent air leaking past the piston. In commercial practice, these seals, which actually form .part of the piston or plunger, are generally cupshaped and are formed of leather, rubber or analogous resilient material; leather, however, 1 being the most common commercial expedient.

In all such devices, a suitable film of lubricating oil is required to relieve friction between the piston or plunger and the cylinder and to assure an air-tight seal between the piston or plunger and the cylinder. Further, when leather sealing cups are utilized, these must be maintained in a relatively soft and pliable condition, and this can best be accomplished by frequent .or continuous oiling. Although these sealing cups are generally treated with oil prior to assembly, they do, of course, gradually give up their oil to thecylinder, if the'cylinder walls them selves are not maintained in satisfactorily lubricated conditions, and eventually dry up and. become. ineffective for the required purpose. Once such sealing cups fail as a result of insufficient lubrication, they can seldom be rejuvenated to good working condition and generally require replacement. In many cases, how

ever, even replacement of the sealing cup does not restore the device to good working condition since, in many cases, dry operation will have resulted also in a scored cylinder wall.

While the application of a few drops of oil to the inside of the cylinder at properly spaced intervals would largely avoid the difliculties above enumerated, it is found that such devices are very seldom given the benefit of such service, with a result that most such devices become inoperative and are discarded and replaced after comparatively short periods of use. It has been suggested that these difi'iculties could be obviated or relieved greatly by supplying the interior of the cylinder with a relatively large volume of oil, but this procedure has been found impractical for the following reasons, to wit:

A. If more than sufiicient oil than is necessary to form a film over the working surfaces of the cylinder and piston is placed in the device by the manufacturer in a free-flowing state, such would inevitably be poured out through one or more of the cylinder vent orifices during shipment and handling prior to installation; and

B. A free-flowing body of lubricant, such as will form a pool in the bottom of the cylinder, even when inserted after installation, appears to be rather rapidly dissipated to atmosphere through one or more of the vent orifices of the cylinder, under normal operating conditions, thus not only exhausting the supply but producing a dirt-collecting nuisance about the exterior ofthe; device.

In view of the above, it is the object of the instant invention to provide an improved 'means .for automatically maintaining the cylinderv and.

plunger in properly lubricated condition over very long periods of usage, to thereby. greatly extend the lives of such devices and completely relieve the owners thereof from any and all responsibility insofar as lubrication is concerned. Hence, in accordance with the invention, I provide a simple and low-cost lubricating means which may be quickly and easily installed by the manufacturer at the time the devices are being assembled, and which operates automatically to meter out lubricant to the cooperating surfaces of the piston or plunger and cylinder in minute .quantities and at a rate controlled by and dependent upon the frequency of usage.

The above and other highly important objects and advantages of the invention will be made apparent from the following specification, claims and appended drawing.

In the accompanying drawing, like characters indicate like parts throughout the several views.

Referring to the drawings:

Fig. 1 is a fragmentary sectional view, with some parts broken away and some parts shown in section, through a door frame and door equipped with a pneumatic door check incorporating the instant invention;

Fig. 2 is a detail sectional view taken on the line 22 of Fig. 1;

Fig. 3 is an enlarged transverse sectional view taken on the line 3-3 of Fig. 2; and

Fig. 4 is a detail view, with some parts shown in section, of a valve for adjustably controlling the rate at which air is allowed to escape from the front or pressure end of the cylinder.

In Fig. l, a door frame is indicated by I and a swinging door by 2. The door 2 is shown as being hinged to the frame I for swinging movements on a vertical axis by means of a conventional hinge or hinges 3.

The spring-operated pneumatically-controlled door closer which, for convenience, is herein referred to as a door check, comprises an elongated cylinder 4, a plunger-rod 5, a piston or plunger 6 mounted fast on the inner end of the plunger rod, and a coil compression spring 1, which is compressed between the piston and the closed rear end 8 of the cylinder 4. By reference to Fig. 2, it will be seen that the plunger rod 5 Works through a suitable piston rod aperture 9 in the closed rear end 8 of the cylinder 4 and that this aperture 9 is of sufficiently greater diameter than the plunger-rod 5 to provide ample clearance for venting of the cylinder space rearwardly of the piston or plunger 5. By further reference to Fig. 2, it will be seen that the pistons or plungers 6 comprise a conventional sealing cup H, which may be assumed to be of the conventional leather variety. The front or pressure end of the cylinder 4 is closed by a head l2 having an axial vent aperture which is adjustably controlled by a valve l3 comprising a screw threaded into the said vent aperture and having a diagonal slot H, shown most clearly in Fig. 4. With this device, the efiective cross-sectional area of the vent aperture is variable by adjustment of the screw valve 13, which is held against accidental movements by means of a compression spring l5.

The-projecting outer or rear end of the plungerrod 5 is pivoted to the door frame by mean of a suitable bifurcated anchoring bracket 6 and pivot pin IT. The front end of the cylinder 4 is anchored to the door 2 for swinging movements with respect thereto by means of an anchoring bracket I8 secured to the door 2 and a-cooperating bifurcated anchoring bracket l9 mounted fast on the head l2 of the cylinder 4. The free ends of the opposite legs .of the bifurcated or U.-shaped anchoring bracket l9 are hook-shaped, as shown best in Fig. l, and are inserted through suitable receiving apertures '20 in the bracket 18 and hooked and fulcrumed over the portions of the bracket adjacent the inner ends of the slot-like apertures 20. This method of pivotally or swingably attaching the cylinder 4 tothe door 2 is one employed in commercial practice.

By reference particularly to Figs. 2 and 3, it will :be noted that the compression spring 1 is of "sufiiciently less diameter than the internal diameter of the cylinder 4 to work freely therein, but

tends to warp and buckle and, hence, does contact and have wiping engagement with the inside of the cylinder at frequent intervals longitudinally thereof. Further, by particular reference to Figs. 2 and 3, it will be seen that the diameter of the plunger-rod 5 is much less than the internal diameter of the spring 1', so as to provide a. rather large annular space between the plunger-rod and spring I.

In accordance with the instant invention, I apply, at the time of assembly of the unit, an annular wick 2| over the plunger-rod 5 and within the coil spring 'I'. This wick 2| is ,of suitable absorbent material, preferably felt, and is elongated to form the cylinder. This cylindrical wick 2| is treated with oil prior to assembly, preferably by soaking the same to, or substantially to, the saturation point. As will be seen by reference to the drawings, this oil-treated wick 2| is of such diameter and length that it will have wiping contact with a number of convolutions of the sprin i when the latter is subject to expansion and compression within the cylinder. Preferably, also, the internal diameter of the wick 2| is such that it Will have wiping contact with the plunger-rod 5 at one or more pointsq'In the preferred embodiment of the invention illustrated, the wick 2| is formed from an elongated strip or ribbon of absorbent material, such as felt, wound helically upon itself to form a cylinder of suitable internal and external diameter and which will, in fact, and by its own elasticity, tend to circumferentially expand against the in:- terior of the coil spring.

For each cycle of operation of the device described, the coil spring I will be first contracted and then expanded, and each time this happens several convolutions of the coil spring 1 will move slightly over the surface of the wick 2| and pick up therefrom a minute quantity of oil which will travel over the surface of the spring and be delivered to the internal surfaces of the cylinder through capillary action. Of course, the several convolutions of the spring also slidably move over the inner surface of the cylinder during each cycle of operation and, of course, this Wiping ac tion of the spring on the cylinder will distribute oil over the interior surface of the cylinder. Of course, it goes without saying that oil deposited on some convolutions of the spring will travel by capillary action to other convolutions of the spring, which will, in turn, transfer the same to surfaces of the cylinder traversed by the piston or plunger 3.

In carrying out the invention, it is important that the cylinder have suflicient length, with respect to the maximum stroke of the piston plunger 6, to at least freely accommodate the cylindrical wick 2| when the piston or plunger 6 is at the extreme of its spring-compressing stroke, so as to positively prevent the wick 2| from being compressed between the piston or plunger 6 and the outer or rear end portion 8 of the cylinder 4. It is not essential that the in terior of the wick 2| engage the plunger-rod 5, but such engagement does have the advantage of providing ample but controlled lubrication between the plunger-rod and the walls of the orifice 9 in the rear end f the cylinder 4.

The wick 2| described holds a relatively great quantity of lubricating oil and, in practice, it has been found that it gives up its oil in very minute quantities, and at a rate controlled by frequency of operation closely approximating that required to maintain the piston or plunger and cylinder in good working condition for remarkably long periods.

My invention has been thoroughly tested and found to be completely satisfactory for the ac complishment of the objectives set forth; and

Y cylinder having closed front and rear ends, the

closed rear end of the cylinder having an axial plunger-rod aperture, a plunger-rod working slidably through said aperture, a plunger fast on the inner end portion of the plunger-rod, a coil compression spring mounted in the cylinder over the plunger-rod and compressed between the plunger and the rear end portion of the cylinder,

the exterior of the spring slidably bearing against the interior of the cylinder, the internal diameter of the spring being materially greater than the exterior diameter of the plunger-rod, and an 1 oil-soaked annular wick mounted over the plunger-rod and within the spring, a plurality of convolutions of said spring having wiping engage-t 4. The structure defined in claim 1 in which the internal length of the cylinder is materially greater than the anticipated normal stroke of the plunger, and in which the distance between the plunger and the inner rear end of the cylinder is greater than the length of the annular wick when the said piston is at the extreme of its inward spring compressing stroke, so that the annular wick will at no time be subject to compression between the plunger and the rear endwick when the said piston is at the extreme of its inward spring compressing stroke, so that the annular wick will at no time be subject to compression between the plunger and the rear end of the cylinder, and said annular wick being axially elongated and of generally cylindrical shape. 7

6. The structure defined in claim 1 in which the internal length of the cylinder is materially greater than the anticipated normal stroke of the plunger, and in which the distance between the plunger and the inner rear end of the cylinder is greater than the length of the annular wick when the said plunger is at the extreme of its inward spring compressing stroke, so that the annular wick will at no time be subjected to compression between the plunger and the rear end of the cylinder, said annular wick comprising a strip of absorbent material helically wound upon itself.

BERT A. QUINN.

References Cited in the file of this patent UNITED STATES PATENTS Bales Oct. 25,v 1949 

